just smudging it will do. you have smudgers you can buy at an art store or if need be just use your finger.

Oh, I see. That means I have been using stencils the wrong way.
When I do the smudging, do I need to do it to the entire drawing?
I'm also wondering how I'll end up with a clean piece of art after smudging.

I always come up with a messy piece of art LOL. I have tried smudging and I think it's best used when you're drawing nature elements like forests and mountains.
I would like to try putting colors on my drawings. Is it better to use pastel colors or paint?